scholarly journals Effect of a surface tension imbalance on a partly submerged cylinder

2017 ◽  
Vol 830 ◽  
pp. 369-386 ◽  
Author(s):  
Stoffel D. Janssens ◽  
Vikash Chaurasia ◽  
Eliot Fried
Keyword(s):  
Surface Tension ◽  
Cross Section ◽  
Cross Sections ◽  
Unit Length ◽  
Pressure Measurements ◽  
Force Component ◽  
Load Bearing Capacity ◽  
Submerged Cylinder ◽  
The Difference ◽  
Practical Implications

We perform a static analysis of a circular cylinder that forms a barrier between surfactant-laden and surfactant-free portions of a liquid–gas interface. In addition to determining the general implications of the balances for forces and torques, we quantify how the imbalance $\unicode[STIX]{x0394}\unicode[STIX]{x1D6FE}=\unicode[STIX]{x1D6FE}_{a}-\unicode[STIX]{x1D6FE}_{b}$ between the uniform surface tension $\unicode[STIX]{x1D6FE}_{a}$ of the surfactant-free portion of the interface and the uniform surface tension $\unicode[STIX]{x1D6FE}_{b}$ of the surfactant-laden portion of the interface influences the load-bearing capacity of a hydrophobic cylinder. Moreover, we demonstrate that the difference between surface tensions on either side of a cylinder with a cross-section of arbitrary shape induces a horizontal force component $f^{h}$ equal to $\unicode[STIX]{x0394}\unicode[STIX]{x1D6FE}$ in magnitude, when measured per unit length of the cylinder. With an energetic argument, we show that this relation also applies to a rod-like barrier with cross-sections of variable shape. In addition, we apply our analysis to amphiphilic Janus cylinders and we discuss practical implications of our findings for Marangoni propulsion and surface pressure measurements.

Effects of Cross-Section Geometry of Capillary on the Evaporation From the Meniscus

2005 ◽  
Author(s):  
Songwan Jin ◽  
Choonghyo Choi ◽  
Kenneth S. Breuer ◽  
Jung Yul Yoo
Keyword(s):  
Surface Tension ◽  
Cross Section ◽  
Evaporation Rate ◽  
Rectangular Channel ◽  
Vortex Motion ◽  
Meniscus Shape ◽  
Four Corners ◽  
The Difference ◽  
Circular Capillary ◽  
Cross Section Geometry

Effects of cross-section geometry of capillary on the evaporation from the meniscus have been investigated by adopting several circular and rectangular capillaries. The evaporating meniscus shape, evaporation rate and flow near the evaporating meniscus of various liquids such as water, ethanol and methanol are determined. The shapes of water and ethanol menisci in circular capillary are quite different from each other due to the difference in surface tension. But the difference in meniscus shapes is relatively small in rectangular channel. The averaged evaporation fluxes in rectangular channel are much larger than that in circular capillary. The rotating vortex motion is observed near the evaporating menisci of ethanol and methanol except for the case of methanol in 200 × 20-μm capillary. The reason for this is considered to be the existence of the corner menisci at the four corners.

scholarly journals Slender body theory for particles with non-circular cross-sections with application to particle dynamics in shear flows

2019 ◽  
Vol 877 ◽  
pp. 1098-1133 ◽  
Author(s):  
Neeraj S. Borker ◽  
Donald L. Koch
Keyword(s):  
Cross Section ◽  
Relative Motion ◽  
Cross Sections ◽  
Stokes Flow ◽  
Unit Length ◽  
Fluid Velocity ◽  
Simple Shear Flow ◽  
Slender Body Theory ◽  
Aspect Ratios ◽  
Cross Sectional Dimension

This paper presents a theory to obtain the force per unit length acting on a slender filament with a non-circular cross-section moving in a fluid at low Reynolds number. Using a regular perturbation of the inner solution, we show that the force per unit length has $O(1/\ln (2A))+O(\unicode[STIX]{x1D6FC}/\ln ^{2}(2A))$ contributions driven by the relative motion of the particle and the local fluid velocity and an $O(\unicode[STIX]{x1D6FC}/(\ln (2A)A))$ contribution driven by the gradient in the imposed fluid velocity. Here, the aspect ratio ($A=l/a_{0}$) is defined as the ratio of the particle size ($l$) to the cross-sectional dimension ($a_{0}$) and $\unicode[STIX]{x1D6FC}$ is the amplitude of the non-circular perturbation. Using thought experiments, we show that two-lobed and three-lobed cross-sections affect the response to relative motion and velocity gradients, respectively. A two-dimensional Stokes flow calculation is used to extend the perturbation analysis to cross-sections that deviate significantly from a circle (i.e. $\unicode[STIX]{x1D6FC}\sim O(1)$). We demonstrate the ability of our method to accurately compute the resistance to translation and rotation of a slender triaxial ellipsoid. Furthermore, we illustrate novel dynamics of straight rods in a simple shear flow that translate and rotate quasi-periodically if they have two-lobed cross-section, and rotate chaotically and translate diffusively if they have a combination of two- and three-lobed cross-sections. Finally, we show the remarkable ability of our theory to accurately predict the motion of rings, retaining great accuracy for moderate aspect ratios (${\sim}10$) and cross-sections that deviate significantly from a circle, thereby making our theory a computationally inexpensive alternative to other Stokes flow solvers.

LOAD-BEARING CAPACITY OF CONCRETE-FILLED STEEL COLUMNS

2009 ◽  
Vol 15 (1) ◽  
pp. 21-33 ◽  
Author(s):  
Artiomas Kuranovas ◽  
Douglas Goode ◽  
Audronis Kazimieras Kvedaras ◽  
Shantong Zhong
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
Cross Sections ◽  
Rectangular Cross Section ◽  
Circular Cross Section ◽  
Steel Tube ◽  
Sustained Load ◽  
Load Bearing Capacity ◽  
Concrete Core ◽  
Load Bearing

This paper represents the analysis of 1303 specimens of CFST experimental data. Test results are compared with EC4 provided method for determining the load‐bearing capacity of these composite elements. Several types of CFSTs were tested: both circular and rectangular cross‐sections with solid and hollow concrete core with axial load applied without and with moment, with sustained load and preloading. For circular cross‐section columns there is a good agreement between the test failure load and the EC4 calculation for both short and long columns with and without moment. For rectangular cross‐section columns the agreement is good except when the concrete cylinder strength was greater than 75 MPa, when many tests failed below the strength predicted by EC4. Preloading the steel tube before filling with concrete seems to have no effect on the strength. This paper also presents the stress distribution, confinement distribution and complete average longitudinal stress‐strain curves for concrete‐filled steel tubular elements. Based on the definition of the “Unified Theory”, the CFST is looked upon as an entity of a new composite material. In this paper, the research achievement of the strength and stability for centrifugal‐hollow and solid concrete filled steel tube are introduced. These behaviours relate to the hollowness ratio and the confining indexes of corresponding solid CFST. If the hollow ratio equals to 0,4–0,5 and over, the N‐ϵ relationship exists in steady descending stage. The critical stress of CFST elements stability is determined as an eccentric member with the initial eccentricity by use of finite element method. Santrauka Straipsnyje analizuojami 1303 betonšerdžių plieninių strypų bandinių eksperimentiniai duomenys. Duomenys lyginami su eurokode 4 pateiktais kompozitinių elementų laikomosios galios nustatymo metodais. Analizuojami šie betonšerdžių plieninių strypų bandinių tipai: pilnaviduriai ir tuščiaviduriai, apskrito ir stačiakampio skerspjūvio kolonos, kurių galuose veikia arba neveikia momentas, su iš anksto pridėta arba ilgalaike apkrova. Apskrito skerspjūvio kolonų laikomosios galios bandymų rezultatai atitinka skaičiavimų reikšmes, apskaičiuotas pagal eurokode 4 pateiktu metodu. Stačiakampio skerspjūvio elementų laikomosios galios reikšmių bandymo rezultatai puikiai atitinka teorines reikšmes, kai betono ritininis stipris nesiekia 75 MPa. Išankstinis elementų apkrovimas poveikio elementų laikomajai galiai beveik neturi. Taip pat nagrinėjami betonšerdžių elementų įtempių būvių pasiskirstymas, betono apspaudimo poveikis ir išilginių deformacijų ir įtempių kreivės. Pateikiama S. T. Zhong „Unifikuota teorija“, kuri nagrinėja kompozitinį elementą kaip visumą. Straipsnyje nagrinėjamos kompozitinio plieninio ir betoninio elemento stiprumo ir pastovumo sąlygos. Tokių elementų reikšmėmis. Jeigu tuštumos santykis lygus 0,4–0,5 ir daugiau, N-ε sąryšis yra kritimo stadijoje. Elgsenos stadijos keičiasi pagal tuštumos koeficientą.

Optimal Design of an Elastic Column of Thin-Walled Cross Section

1968 ◽  
Vol 35 (2) ◽  
pp. 285-288 ◽  
Author(s):  
N. C. Huang ◽  
C. Y. Sheu
Keyword(s):  
Optimal Design ◽  
Cross Section ◽  
Wall Thickness ◽  
Cross Sections ◽  
Unit Length ◽  
Compressive Load ◽  
Median Line ◽  
Vertical Column ◽  
Thin Walled ◽  
Allowable Compressive Stress

This paper treats the optimal design of a vertical column that is built-in at the lower end. In addition to its own weight, the column is to carry an axial compressive load at its unsupported upper end. The column is to be designed as a thin-walled tube. The median line is to be the same for all cross sections; the wall thickness, though constant along the median line of any cross section, is allowed to vary along the length of the tube. Accordingly, the weight per unit length of the tube is proportional to the bending stiffness. For given length and total weight, the variation of the wall thickness along the column is to be determined to maximize the critical value of the compressive load at the upper end. The influence of a maximum allowable compressive stress on the design is also investigated.

scholarly journals Aeroelastic and Aerodynamic Tests of Wind Turbine with Various Polygonal Towers

2021 ◽  
Vol 11 (24) ◽  
pp. 11740
Author(s):  
Yong Chul Kim
Keyword(s):  
Cross Section ◽  
Drag Force ◽  
Wind Turbines ◽  
Cross Sections ◽  
Circular Cross Section ◽  
Aerodynamic Characteristics ◽  
Azimuth Angle ◽  
Pressure Measurements ◽  
Force Coefficients ◽  
Mean Wind Speed

Traditionally, circular cross-section towers have been used as supporting systems of wind turbines, but weaknesses have become apparent with recent upsizing of wind turbines. Thus, polygonal cross-section towers have been proposed and used in Europe. In this study, the effects of polygonal cross-sections on the aeroelastic and aerodynamic characteristics of wind turbines were examined through a series of wind tunnel tests. Aeroelastic tests showed that a square cross-section tower showed instability vibrations, and polygonal cross-section towers showed limited vibrations for tower-only cases. However, for wind turbines with various polygonal cross-section towers, no instability vibrations were observed, and displacements increased proportionally to the square of mean wind speed. Furthermore, pressure measurements showed that local force coefficients changed largely depending on wind direction and azimuth angle. Local drag force coefficients decreased with increasing number of tower sides, approaching those of the tower-only case, and local lift force coefficients showed larger absolute values than those of the tower-only case. The maximum mean and fluctuating drag force and the maximum fluctuating lift coefficients at each height decreased with increasing number of tower sides.

scholarly journals CRITICAL EXPERIMENT OF THORIUM LOADED THERMAL CORES AT KUCA (1) A NEW CRITICAL EXPERIMENT OF THORIUM LOADED CORE WITH HARDER NEUTRON SPECTRUM IN KUCA

2021 ◽  
Vol 247 ◽  
pp. 09013
Author(s):  
Tadafumi Sano ◽  
Jun-ichi Hori ◽  
Jeaong Lee ◽  
Yoshiyuki Takahashi ◽  
Kazuki Takahashi ◽  
...  
Keyword(s):  
Cross Section ◽  
Neutron Spectrum ◽  
Cross Sections ◽  
Capture Cross Section ◽  
The Other ◽  
Capture Cross ◽  
Delayed Neutron ◽  
Integral Evaluation ◽  
Critical Experiment ◽  
The Difference

In order to perform integral evaluation of 232Th capture cross section, a series of critical experiments for thorium-loaded and solid-moderated cores in KUCA had been carried out. In these experimental cores, H/235U nuclide ratio ranged about from 150 to 315, and 232Th/235U nuclide ratio ranged about from 13 to 19. In this study, a new critical experiment with Th loaded core in KUCA, which had about 70 of the H/235U ratio and 12.7 of 232Th/235U ratio, was carried out. As results, the excess reactivity was 0.086 ± 0.003 (% dk/k) and the keff was 1.0009 ± 0.0003, where the effective delayed neutron fraction was 7.656E-3. The keff was also calculated by MVP3.0 with different nuclear libraries. The respective calculations with JENDL-4.0, JENDL-3.3 and ENDF/B-VII.0 lead to 1.0056 ± 0.0086 (%), 1.0048 ± 0.0085 (%) and 1.0056 ± 0.0086 (%).On the other hand, the further MVP3.0 calculations, where only the 232Th cross sections were taken from JENDL-4.0, JENDL-3.3 or ENDF/B-VII.0 but all other nuclides were done from JENDL-4.0, were carried out to examine an impact of the difference of 232Th cross section among these nuclear libraries to the keff. The keff calculated with respective 232Th cross sections from JENDL-3.3 and ENDF/B-VII.0 was 1.0038 ± 0.0086 (%) and 1.0040 ± 0.0086 (%).

scholarly journals Columns with Different Cross Section using ANSYS Work Bench

2019 ◽  
Vol 9 (2S4) ◽  
pp. 469-473
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Metal Plate ◽  
Moment Of Inertia ◽  
Strength Of Materials ◽  
Metal Plates ◽  
The Difference ◽  
Specific Material ◽  
Circular Bar ◽  
Ansys Workbench

In this paper we are going to analyze the strength of material and deflection due to applying load on the column. The column of different materials will be cross sectioned and will present the difference of strength of materials by ANSYS workbench. The strength of material will depend upon the young’s modulus and moment of inertia of the metal plate. We use different size of metal plates such as I-section, circular bar, rectangular bar and square bar for a specific material to know the strength of material when a load applied on the cross sections. In this paper we taken a condition that one side of column is fixed and another side is free when load is applying on the column.

scholarly journals Numerical modelling of the bearing capacity of a beam cross-section

2021 ◽  
Vol 1208 (1) ◽  
pp. 012043
Author(s):  
Besim Demirović ◽  
Rašid Hadžović ◽  
Nedim Osmić
Keyword(s):  
Numerical Modelling ◽  
Bearing Capacity ◽  
Cross Section ◽  
Cross Sections ◽  
Nonlinear Behavior ◽  
Load Bearing Capacity ◽  
Cross Sectional ◽  
Linear And Nonlinear ◽  
The Cross ◽  
Iterative Procedures

Abstract The paper presents a procedure for numerical modelling of the rod cross-section bearing capacity. Equilibrium between cross sectional forces and cross-sectional stresses is determined by iterative procedures. According to the described procedure, the load-bearing capacity of the cross-section is determined according to the isotropic linear and nonlinear behavior of the material, for homogeneous and inhomogeneous cross-sections. The nonlinear behavior of the material reduces the stiffness of the cross section of the rod EA and EI, with a significant increase in the deformation values ε and κ. The applicability of the calculation and analysis of obtained results is presented using numerical examples.

scholarly journals A Hybrid Surface Reference Technique and Its Application to the TRMM Precipitation Radar

2004 ◽  
Vol 21 (11) ◽  
pp. 1645-1658 ◽  
Author(s):  
R. Meneghini ◽  
J. A. Jones ◽  
T. Iguchi ◽  
K. Okamoto ◽  
J. Kwiatkowski
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Tropical Rainfall Measuring Mission ◽  
Absolute Difference ◽  
Precipitation Radar ◽  
Weather Radars ◽  
The Difference ◽  
Rain Events ◽  
Using Data ◽  
Cross Track

Abstract Satellite weather radars that operate at attenuating wavelengths require an estimate of path attenuation to reconstruct the range profile of rainfall. One such method is the surface reference technique (SRT), by which attenuation is estimated as the difference between the surface cross section outside the rain and the apparent surface cross section measured in rain. This and the Hitschfeld–Bordan method are used operationally to estimate rain rate using data from the precipitation radar (PR) aboard the Tropical Rainfall Measuring Mission (TRMM) satellite. To overcome some of the problems associated with the latest operational version of the SRT, a hybrid surface reference is defined that uses information from the along-track and cross-track variations of the surface cross sections in rain-free areas. Over ocean, this approach eliminates most of the discontinuities in the path-attenuation field. Self-consistency of the estimates is tested by processing the orbits backward as well as forward. Calculations from 2 weeks of PR data show that 90% of the rain events over ocean for which the SRT is classified as reliable or marginally reliable are such that the absolute difference between the forward and backward estimates is less than 1 dB.

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